Editorial Commentary: Both Osteochondral Allograft Transplantation and Autologous Chondrocyte Implantation Are Valuable Treatment Options for Patellofemoral Joint Cartilage Defects.

The patellofemoral (PF) joint is a challenging location to repair cartilage. Although both osteochondral allograft transplantation (OCA) and autologous chondrocyte implantation (ACI) are established as standard therapies for cartilage repair, most treatment algorithms continue to favor ACI for the PF joint, which shows a high rate of success. Today, however, OCA is a treatment of choice to revise prior failed PF cartilage repair. The positive outcomes in this setting encourage indicating OCA for select primary cartilage repair patients, namely those with defects that are uncontained or osteochondral. An advantage of OCA over ACI is that the tissue is more robust and there may be less need for osteotomy to unload the PF joint. Even for ACI, tibial tubercle osteotomy is reserved for patients with abnormal patellar tracking and/or patellar height. In terms of return to sports, realistic expectations are required. Both ACI and OCA are valuable treatment options for PF cartilage defects.

Increased Host Bone Marrow Edema on 6-Month MRI Is a Risk Factor for Osteochondral Allograft Failure.

PURPOSE: To evaluate the presence of host bone marrow edema (BME) surrounding osteochondral allograft (OCA) plugs on routine 6-month postoperative magnetic resonance imaging (MRI) and to determine whether such BME is correlated with subsequent failure. METHODS: The present study was approved under our institutional review board-approved database (#2020-2123). We included patients who underwent cartilage repair with OCA for focal chondral and osteochondral defects of the distal femur by 2 senior surgeons between January 2016 and May 2021 with minimum 2-year follow-up. OCA is frequently performed with concomitant procedures, and therefore ligament reconstruction, meniscal surgery, and osteotomy were not exclusion criteria. Failure was defined as (1) poor clinical outcome with graft collapse on follow-up MRI or second-look arthroscopy, (2) primary OCA removal or revision, or (3) conversion to unicompartmental or total knee arthroplasty. Routine MRI scans were performed at 6 ± 2 months postoperatively. All postoperative MRI scans were reviewed from our imaging record by 2 blinded fellowship-trained orthopaedic surgeons. Patients were divided for analyses into 2 groups: BME ≥10 cm3 versus BME <10 cm3. RESULTS: Of the 85 patients eligible for the study, 56 patients (30 female, mean age 31.69 ± 11.34 years) had a minimum 2-year follow-up. Nonfailure cases had a mean clinical follow-up of 3.13 ± 0.93 years. The mean time from surgery to failure in our cohort was 1.67 ± 0.91 years. There were 12 (21.4%) patients with BME ≥10 cm³ and 44 (78.6%) patients with BME <10 cm³. No statistically significant differences were found between groups when compared for sex, age, body mass index, OCA size, time to MRI, mean follow-up, number of plugs, graft location, diagnosis, previous surgeries, or concomitant procedures. All OCA failures of the study cohort were in the BME ≥10 cm³ group, representing 50% of this group (P < .001). Kaplan-Meier survival analysis with the log-rank test demonstrated significant difference in survival distributions between groups (P < .001). Patients who ultimately failed had a mean BME volume of 18.49 ± 5.82 cm3, while the nonfailure group had a mean volume of 4.66 ± 4.97 cm3 (P < .001). Cutoff values around 10 cm³ in receiver operating characteristic curve analysis demonstrated 100% sensitivity and close to 90% specificity for OCA failure diagnosis. CONCLUSION: Host BME with a volume greater than 10 cm³ on 6-month postoperative MRI is predictive of an increased subsequent failure rate after OCA transplantation with a failure rate of 50%. LEVEL OF EVIDENCE: Level III, cohort study.

Differential analysis of the impact of lesions' location on clinical and radiological outcomes after the implantation of a novel aragonite-based scaffold to treat knee cartilage defects.

PURPOSE: There is limited comparative evidence on patient outcomes following cartilage repair in various knee compartments. The aim of this study was to compare clinical and imaging outcomes after treating cartilage defects in femoral condyles and trochlea with either an aragonite-based scaffold or surgical standard of care (SSoC, i.e., debridement/microfractures) in a large multicentre randomized controlled trial. METHODS: 247 patients with up to three knee joint surface lesions (ICRS grade IIIa or above) in the femoral condyles, trochlea or both ("mixed"), were enrolled and randomized to surgery with either a cell-free aragonite scaffold or SSoC. Patients were followed for up to 48 months by analysing subjective scores (KOOS and IKDC), radiological outcomes (defect filling on MRI), as well as treatment failure rates and adverse events. A differential analysis of outcomes for condylar, trochlear and mixed lesions was performed. RESULTS: The scaffold group significantly outperformed the SSoC group regardless of lesion location with statistically significantly better KOOS Overall scores at 24 months (all p ≤ 0.0009) and 48 months (all p ≤ 0.02). Similar results were observed for KOOS subscales and IKDC scores. For KOOS responder rates, superiority of the implant group was demonstrated at 24, 36, and 48 months (all p ≤ 0.004). Higher defect filling on MRI for implants was observed for all locations. Lower treatment failure rates for the implant were observed in condylar and mixed lesions. CONCLUSION: The aragonite-based scaffold was safe and effective regardless of the defect location, providing superior clinical and radiological outcomes compared to SSoC up to four years follow-up. LEVEL OF EVIDENCE: I - Randomized controlled trial.

Editorial Commentary: A Posterior Tibial Tubercle Relative to the Trochlear Groove Is Associated With Increased Risk of Patellofemoral Arthritis: The Sagittal Tibial Tubercle-Trochlear Groove Distance.

Arthritis of the patellofemoral compartment affects up to 24% of women and 11% of men over the age of 55 years who have symptomatic osteoarthritis of the knee. Patellofemoral cartilage lesions have been associated with several different geometric measures of patellar alignment, including the tibial tubercle-trochlear groove (TTTG) distance, trochlear sulcus angle, trochlear depth, and patellar height. Recently, there has been interest in the sagittal TTTG distance, which measures the position of the tibial tubercle with respect to the trochlear groove. This measurement is now being used in patients presenting with patellofemoral pain and/or cartilage pathology and may help guide surgical decision making as we gain more data on how changing the tibial tubercle alignment relative to the patellofemoral joint can improve outcomes. For now, there are not enough data to support isolated anteriorization tibial tubercle osteotomy in patients with patellofemoral chondral wear based on the sagittal TTTG distance. However, as we better understand geometric measures as risk factors for patellofemoral arthritis, realignment at a young age might be recommended as a preventative measure against end-stage osteoarthritis.

Lower donor site morbidity with hamstring and quadriceps tendon autograft compared with bone-patellar tendon-bone autograft after anterior cruciate ligament reconstruction: a systematic review and network meta-analysis of randomized controlled trials.

PURPOSE: To perform a meta-analysis of RCTs evaluating donor site morbidity after bone-patellar tendon-bone (BTB), hamstring tendon (HT) and quadriceps tendon (QT) autograft harvest for anterior cruciate ligament reconstruction (ACLR). METHODS: PubMed, OVID/Medline and Cochrane databases were queried in July 2022. All level one articles reporting the frequency of specific donor-site morbidity were included. Frequentist model network meta-analyses with P-scores were conducted to compare the prevalence of donor-site morbidity, complications, all-cause reoperations and revision ACLR among the three treatment groups. RESULTS: Twenty-one RCTs comprising the outcomes of 1726 patients were included. The overall pooled rate of donor-site morbidity (defined as anterior knee pain, difficulty/impossibility kneeling, or combination) was 47.3% (range, 3.8-86.7%). A 69% (95% confidence interval [95% CI]: 0.18-0.56) and 88% (95% CI: 0.04-0.33) lower odds of incurring donor-site morbidity was observed with HT and QT autografts, respectively (p < 0.0001, both), when compared to BTB autograft. QT autograft was associated with a non-statistically significant reduction in donor-site morbidity compared with HT autograft (OR: 0.37, 95% CI: 0.14-1.03, n.s.). Treatment rankings (ordered from best-to-worst autograft choice with respect to donor-site morbidity) were as follows: (1) QT (P-score = 0.99), (2) HT (P-score = 0.51) and (3) BTB (P-score = 0.00). No statistically significant associations were observed between autograft and complications (n.s.), reoperations (n.s.) or revision ACLR (n.s.). CONCLUSION: ACLR using HT and QT autograft tissue was associated with a significant reduction in donor-site morbidity compared to BTB autograft. Autograft selection was not associated with complications, all-cause reoperations, or revision ACLR. Based on the current data, there is sufficient evidence to recommend that autograft selection should be personalized through considering differential rates of donor-site morbidity in the context of patient expectations and activity level without concern for a clinically important change in the rate of adverse events. LEVEL OF EVIDENCE: Level I.

Establishing minimal detectable change thresholds for the international knee documentation committee and Kujala scores at one and two years after patellofemoral joint arthroplasty.

PURPOSE: To define the minimal detectable change (MDC) for the international knee documentation committee (IKDC) and Kujala scores one and two years after patellofemoral joint arthroplasty (PFA). METHODS: A distribution-based method (one-half the standard deviation of the mean difference between postoperative and preoperative outcome scores) was applied to establish MDC thresholds among 225 patients undergoing primary PFA at a single high-volume musculoskeletal-care center. Stability of change in MDC achievement was explored by quantifying the proportion of achievement at one- and two-year postoperative timepoints. Multivariable logistic regression analysis was performed to explore the association between sociodemographic and operative features on MDC achievement. RESULTS: MDC thresholds for the Kujala score were 10.3 (71.1% achievement) and 10.6 (70.4% achievement) at one- and two years, respectively. The MDC thresholds for the IKDC score were 11.2 (78.1% achievement) and 12.3 (69.0% achievement) at one- and two years, respectively. Predictors of achieving the MDC for the Kujala and IKDC scores at both time points were lower preoperative Kujala and IKDC scores, respectively. Preoperative thresholds of ≤ 24.1 and 7.6 for the Kujala and IKDC scores, respectively, were associated with a 90% MDC achievement probability. When preoperative thresholds approached 64.3 and 48.3 for the Kujala and IKDC, respectively, MDC achievement probability reduced to 50%. CONCLUSION: The MDC thresholds for the Kujala and IKDC scores two years after PFA were 10.6 and 12.3, respectively. Clinically significant health status changes were maintained overall, with a slight decrease in achievement rates between one and two years. MDC achievement was associated with disability at presentation, and several probability-based preoperative thresholds were defined. These findings may assist knee surgeons with patient selection and the decision to proceed with PFA by better understanding the patient-specific propensity for MDC achievement. LEVEL OF EVIDENCE: IV, retrospective case series.

Proximal bone block with distal screw trajectory improves mechanical stability during distalization tibial tubercle osteotomy.

PURPOSE: The purpose of this study was to quantify differences in mechanical stability of a wedge-shaped distalization tibial tubercle osteotomy (TTO) with a standard technique, versus a modified technique with use of a proximal bone block and distally angled screw trajectory. METHODS: Ten fresh-frozen cadaver lower extremity specimens (five matched pairs) were utilized. Within each specimen pair, one specimen was randomly assigned to undergo a standard distalization osteotomy fixed with two bicortical 4.5-mm screws oriented perpendicular to the long axis of the tibia, and the other to undergo a distalization osteotomy with modified fixation utilizing a proximal bone block and distally angled screw trajectory. Each specimen's patella and tibia were mounted on a servo-hydraulic load frame using custom fixtures (MTS Instron). The patellar tendon was dynamically loaded to 400 N at a rate of 200 N/second for 500 cycles. Following the cyclic loading, loading to failure was done at 25 mm/min. RESULTS: The modified distalization TTO technique demonstrated significantly higher average load to failure compared to the standard distalization TTO technique (1339 N vs. 844.1 N, p < 0.001). Average maximum tibial tubercle displacement during cyclic loading was significantly smaller in the modified TTO technique group compared to the standard TTO technique (1.1 mm vs. 4.7 mm, p < 0.001). CONCLUSION: This study demonstrates that distalization TTO utilizing a modified technique with a proximal bone block and distally aimed screws is biomechanically superior to standard distalization TTO without proximal bone block and screw trajectory perpendicular to the long axis of the tibia. This increased stability may aid in reducing the reported higher complication rates (including loss of fixation, delayed union and nonunion) following distalization TTO, although future clinical outcome studies are warranted.

Many Radiographic and Magnetic Resonance Imaging Assessments for Surgical Decision Making in Pediatric Patellofemoral Instability Patients Demonstrate Poor Interrater Reliability.

PURPOSE: To evaluate the interrater reliability of several common radiologic parameters used for patellofemoral instability and to attempt to improve reliability for measurements demonstrating unacceptable interrater reliability through consensus training. METHODS: Fifty patients with patellar instability between the ages of 10 and 19 years were selected from a prospectively enrolled cohort. For measurements demonstrating unacceptable interrater reliability (intraclass correlation coefficient [ICC]: <0.6), raters discussed consensus methods to improve reliability and re-examined a subset of 20 images from the previous set of images. If reliability was still low after the second round of assessment, the measure was considered unreliable. RESULTS: Of the 50 included subjects, 22 (44%) were male and the mean age at the time of imaging was 14 ± 2 years. With 1 or fewer consensus training sessions, the interrater reliability of the following radiograph indices were found to be reliable: trochlea crossing sign (ICC: 0.625), congruence angle (ICC: 0.768), Caton-Deshamps index (ICC: 0.644), lateral patellofemoral angle (ICC: 0.768), and mechanical axis deviation on hip-to-ankle alignment radiographs (ICC: 0.665-0.777). Reliable magnetic resonance imaging (MRI) indices were trochlear depth (ICC: 0.743), trochlear bump (ICC: 0.861), sulcus angle (ICC: 0.684), patellar tilt (ICC: 0.841), tibial tubercle to trochlear groove distance (ICC: 0.706), effusion (ICC: 0.866), and bone marrow edema (ICC: 0.961). CONCLUSIONS: With 1 or fewer consensus training sessions, the interrater reliability of the following patellofemoral indices were found to be reliable for trochlear morphology: trochlea crossing sign and congruence angle on radiograph and trochlear depth, trochlear bump, and sulcus angle on MRI. Reliable patellar position measurements included: Caton-Deshamps index and lateral patellofemoral angle on radiograph and patellar tilt and tibial tubercle to trochlear groove distance on MRI. Additional global measurements (e.g., mechanical axis deviation on standing radiographs) and MRI assessments demonstrated acceptable reliability. LEVEL OF EVIDENCE: II, prospective diagnostic study.

Safety and Efficacy of an Amniotic Suspension Allograft Injection Over 12 Months in a Single-Blinded, Randomized Controlled Trial for Symptomatic Osteoarthritis of the Knee.

PURPOSE: The purpose of this study is to determine the efficacy of amniotic suspension allograft (ASA) compared to hyaluronic acid (HA) and saline at up to 12 months of follow-up through the use of patient-reported outcomes, immunoglobulin levels, and anti-human leukocyte antigen (HLA) levels. METHODS: Within this multicenter study, 200 patients were randomized 1:1:1 to a single intra-articular injection of saline, HA, or ASA. Patient-reported outcomes, including Knee Injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale (VAS) score, were collected at multiple time points (baseline, 1 week, 6 weeks, 3 months, 6 months) out to 12 months to assess improvements in pain and function. Radiographs at baseline and 12 months were taken to determine radiographic changes, while blood was collected at baseline, 6 weeks, and 6 months to determine changes in immunoglobulins and anti-HLA levels. Statistical analyses were performed using last observation carried forward and mixed effects model for repeated measures. RESULTS: Treatment with ASA resulted in significant improvements in KOOS and VAS scores that were maintained through 12 months (P < .05). Treatment with ASA resulted in a 63.2% responder rate at 12 months using the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International simplified definition. There were no significant differences between groups for radiographic measures in the index knee, immunoglobulins, C-reactive protein, or anti-HLA serum levels (P > .05). The number and type of adverse events (AEs) reported for ASA were comparable to the HA injection group, while no treatment-emergent AEs were reported for the saline group. CONCLUSIONS: This randomized controlled trial of ASA vs HA and saline for the treatment of symptomatic knee osteoarthritis demonstrated clinically meaningful improved outcomes with ASA over the controls out to 12 months postinjection. No concerning immunologic or adverse reactions to the ASA injection were identified with regards to severe AEs, immunoglobulin, or anti-HLA levels. LEVEL OF EVIDENCE: Level I, randomized controlled multicenter trial.

How to Address the Medial Patellofemoral Ligament, Tibial Tubercle, and Articular Cartilage in Patients With Recurrent Patellar Instability.

Patellofemoral instability is a common pathology especially in the adolescent female population.1,2 Prompt diagnosis and management is critical to prevent future episodes of instability as well as to reduce the risk of cartilaginous injury to the patellofemoral articular surface. Initial management of a first-time patellar dislocation has historically been nonsurgical; however, the presence of intra-articular loose bodies or osseocartilaginous injury may require surgical intervention.3,4 More recent evidence has shown patients with specific risk factors such as skeletal immaturity, an incompetent medial soft-tissue sleeve, family history of patellar dislocation, elevated tibial tubercle to trochlear groove distance, patella alta, and high-grade trochlear dysplasia experience high rates of re-dislocation after initial nonsurgical management.4-9 Based on this, the provider needs to consider these risk factors and the possibility of initial surgical management in these patient populations following a first-time patellar dislocation. Surgical options for management of patellar instability and cartilaginous injury include medial patellofemoral ligament repair, medial patellofemoral ligament reconstruction, tibial tubercle osteotomy, and various cartilaginous repair/restoration procedures. It is important to be knowledgeable about the clinical and anatomic/radiographic risk factors associated with patients presenting with patellar instability, the algorithm for treatment, the indications and surgical technique for medial patellofemoral ligament reconstruction and tibial tubercle osteotomy, and management of cartilaginous injury to the patellofemoral joint.

Optimizing Anterior Cruciate Ligament (ACL) Outcomes: What Else Needs Fixing Besides the ACL?

This review focuses on the management of anterior cruciate ligament (ACL) reconstruction patients when other concomitant pathology may need to be addressed at the time of surgery. Given the role of the posterior horn of the medial meniscus in preventing osteoarthritis progression and contributing to knee stability, medial meniscus repair should always be considered when performing ACL reconstruction. Meniscal transplant may also be appropriate in select patients with normal knee alignment and absent of cartilage abnormalities in the compartment. Varus alignment with a varus thrust or increased posterior tibial slope will increase stress on the ACL graft and may predispose to early failure. Alignment should be assessed with appropriate radiographs and corrective osteotomy in isolation or in conjunction with ACL reconstruction should be considered for certain patients. Low-grade medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries can be treated nonsurgically prior to ACL reconstruction. These are frequently missed with either physical examination or radiographic imaging. High-grade LCL injuries are often treated with repair versus reconstruction in conjunction with ACL reconstruction depending on the timing of the injury. When chronic MCL injuries show opening in extension, MCL reconstruction may be needed in addition to the ACL reconstruction to improve outcome. The role of extra-articular reconstruction or anterolateral ligament (ALL) reconstruction remains controversial but may have a role in protecting rotatory stability in primary ACL reconstruction for high-risk patients, and in the revision setting. Cartilage lesions noted in the setting of ACL injury should be considered. Small, asymptomatic lesions in locations unrelated to the ACL injury may not necessitate additional intervention. Large symptomatic lesions may require additional cartilage restoration procedures at the time of ACL reconstruction or in a staged fashion. In this ICL, we will address the diagnosis, management, and surgical indications of other concomitant pathology associated with ACL ruptures.

Patellar Instability and Dislocation: Optimizing Surgical Treatment and How to Avoid Complications.

Patellar instability is a common problem seen by the orthopedic surgeon. Surgery is indicated in recurrent dislocation to improve patellar tracking and ligamentous restraint in order to decrease risk of recurrence, osteochondral injury, and eventual progression to arthritis. Preoperative imaging studies identify anatomic risk factors that increase risk of patellar dislocation to inform surgical decision making. Surgical management starts with medial patellofemoral ligament reconstruction, which is effective in many cases. Tibial tubercle osteotomy realigns the extensor mechanism and is useful in cases of lateralized tibial tubercle or patella alta. For patients with trochlear dysplasia, both tibial tubercle osteotomy and trochleoplasty are options to prevent recurrent dislocation. Chondral lesions are common and, depending upon symptomology and size, can be addressed with débridement, structural grafting, or cell-based treatment. To maximize outcomes, comprehensive preoperative diagnosis and planning must be combined with meticulous surgical technique. Unfortunately, there is minimal evidence to guide when a soft-tissue ligament reconstruction is sufficient versus when is it necessary to correct and alter the bony anatomy. This chapter covers the individualized decision making and surgical pearls for these techniques to improve outcomes and minimize perioperative complications.

Patellofemoral Arthroplasty Surgical Technique: Lateral or Medial Parapatellar Approach.

BACKGROUND: Patellofemoral arthroplasty (PFA) is an emerging treatment for patients with isolated patellofemoral compartment osteoarthritis. The medial parapatellar approach is the standard arthrotomy but has been shown in total knee arthroplasty to damage the patellar blood supply and increase postoperative patellar instability. The lateral parapatellar approach is an alternative that may reduce the risk of these outcomes. The purpose of this study is to compare the radiographic measures of patellar tracking and patient-reported outcomes of the medial and lateral parapatellar approaches in PFA. METHODS: Between 2012 and 2019, a retrospective review was performed of 136 knees undergoing PFA at a single institution. Patients were separated by preoperative congruence angle and then surgical approach into 3 cohorts. Preoperative and postoperative patellar tilt and congruence angle were measured. Preoperative and minimum 6-month postoperative patient-reported outcomes scores were collected. RESULTS: There were no significant differences in the mean postoperative congruence angle and postoperative patient-reported outcomes among the 3 cohorts. Mean postoperative patellar tilt was normalized only in the abnormal congruence angle/lateral approach group to 2.80° (standard error, 1.85). CONCLUSION: Congruence angle was improved regardless of surgical approach. Patellar tilt was normalized only for the lateral approach in patients with abnormal preoperative congruence angle. There were no significant differences in preoperative and postoperative scores between groups except for preoperative 12-item Short Form Mental Health Survey scores. This study supports that the lateral approach offers improved postoperative patellar tilt compared to a medial approach for PFA while achieving similar patient-reported outcomes.

Editorial Commentary: Medial Patellofemoral Ligament Repair Versus Reconstruction: Still a Question or a Clear Winner?

Controversy persists regarding appropriate treatment of patellar instability. As surgeons move to a more aggressive approach, medial imbrication and medial patellofemoral ligament repair are waning in popularity whereas medial patellofemoral ligament reconstruction has become the standard of care. Techniques vary between surgeons, and consensus remains elusive.

Adolescent and Caregiver-derived Utilities for Traumatic Patella Dislocation Health States.

INTRODUCTION: The treatment of a first-time traumatic patella dislocation in children and adolescents remains controversial. Preference-based health utility assessments can provide health-related quality of life information for orthopaedic conditions and their subsequent treatment. The purpose of this study was to determine utilities for pediatric acute traumatic patella dislocation and subsequent treatment health states from both children with patellar dislocation, and their parents. METHODS: Adolescents with acute first-time patella dislocations and their parents were identified. Six patella dislocation health states were defined: (1) Immediate post injury (Injury), (2) Postdislocation and nonoperative treatment with physical therapy (Rehabilitation), (3) Immediately poststabilization surgery (Postsurgical), (4) Recurrent dislocation after treatment (Recurrent dislocator), (5) Stable knee after initial treatment but unable to participate in sport at previous level (Stable return to lower function), and (6) Stable knee after initial treatment and fully able to participate in sport at previous level (Stable return to same function). Classic feeling thermometer utilities acquisition was performed, with self-report (patient) and proxy-report (parent) interviews performed separately. Patients' physical activity levels were collected using the UCLA Activity Score and the HSS Pedi-FABS. Comparisons between groups were made using Mann-Whitney U test and Wilcoxon signed-rank test. RESULTS: Ninety-five adolescents and 95 parents were included. Median (interquartile range) patient utilities for Injury, Rehabilitation, Postsurgical, Recurrent dislocator, Stable return to lower function, and Stable return to same function health states were: 25 (10 to 45), 50 (35 to 62.5), 30 (15 to 48.5), 20 (10 to 40), 70 (50 to 80), and 100 (100 to 100), respectively. Caregiver-derived utilities for children going through these health states were: 25 (10 to 49.5), 50 (25 to 60), 40 (15 to 60), 20 (5 to 40), 60 (50 to 77.5), and 100 (100 to 100). Stable return to a lower function was assigned a significantly higher utility by adolescents than their caregivers (P=0.03); highly active adolescents assigned a significantly higher utility to achieving a stable return to same function (P=0.02) while assigning significantly lower utility to health states in which they were not fully participating in sport. CONCLUSIONS: Adolescents and their parents felt that successful treatment of an acute patella dislocation was equivalent to perfect health (utility=1); however, adolescents assigned a significantly higher utility to a stable but lower functioning health state compared with their parents. Baseline functional status is an important modifier of health state preference-highly active adolescents assign a significantly greater disutility to health states in which they are not participating in sports at their regular level of play. These findings provide insight into the health-related quality of life impact for acute patella dislocations and their management, and potentially support minimizing time out of play and more aggressive treatment of first time acute patellar dislocations in athletic adolescents. LEVEL OF EVIDENCE: Level III.

Return to Sports After Tibial Tubercle Osteotomy for Patellofemoral Pain and Osteoarthritis.

PURPOSE: To determine the rate of return to sports and clinical outcomes after anteromedialization (AMZ) tibial tubercle osteotomy (TTO) for patients with patellofemoral pain and/or osteoarthritis. METHODS: This study is a retrospective case series of consecutive patients who underwent unilateral or staged bilateral AMZ TTO for a primary diagnosis of patellofemoral pain or arthritis. Included were all patients with minimum 1-year follow-up. The indication for surgery was failure of at least 6 months of nonoperative treatment. Simultaneous tubercle distalization or proximal-medial soft-tissue procedures were excluded; however, prior patellar instability procedures did not prohibit inclusion if there was no recurrence. A diagnostic arthroscopy was performed to evaluate the cartilage surfaces; AMZ TTO was performed by use of a freehand technique and two 4.5-mm fully threaded screws for fixation. A gradual return to activities was permitted at 6 months; however, contact sports were prohibited until 9 months postoperatively. Patients were evaluated retrospectively for participation in sports using a questionnaire about the level of participation, return to sporting activities, and Kujala score. Statistical analysis included 1-way analysis of variance and χ2 or Fisher exact and paired t tests. RESULTS: Forty-eight patients played sports within 3 years before surgery. The majority were female patients (84.2%). The average age at surgery was 29.6 years, with an average follow-up period of 4.6 years. The average Kujala score improved from 51.2 to 82.6 (P < .0001); the average pain score improved from 4.1 to 1.8 (P < .001). Of the patients, 83.3% returned to at least 1 sport on average 7.8 months postoperatively. Of these, 77.5% believed they returned to sports at the same level or a higher level. CONCLUSIONS: Patients undergoing AMZ TTO for patellofemoral pain or arthritis had an 83.3% rate of return to 1 or more sporting activities at an average of 7.8 months after surgery, with many patients returning at the same level or a higher level of intensity compared with their preoperative state. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Magnetic Resonance Imaging Validation of Tibial Tubercle Transfer Distance in the Fulkerson Osteotomy: A Clinical and Cadaveric Study.

PURPOSE: To validate the medialization and anteriorization distances, and the osteotomy angle of anteromedialization tibial tubercle osteotomies using postoperative axial imaging. METHODS: From March 2004 to August 2015, 117 consecutive patients who underwent anteromedialization osteotomies of the tibial tubercle by a single surgeon were identified. Only patients with pre- and postoperative magnetic resonance imaging (MRI) studies were included. Using MRI multiplanar reformats, distances that the tibial tubercle was translated medially (medialization) and anteriorly (anteriorization) were measured. In addition, the osteotomy angle was measured on the postoperative MRI. The measured values were compared with intraoperative estimates. Tibial tubercle osteotomies were then performed on 3 cadaveric knee specimens and imaged with pre- and postprocedure MRIs to correlate intraoperative measurements with MRI findings. RESULTS: A total of 40 patients (41 knees) (34.2%) had both pre- and postoperative MRIs and were included. Compared with intraoperative assessment, MRI measured medialization values average 94.7% (standard deviation [SD] 37.7) of dictated values (P = .1). MRI measured anteriorization averaged less than half of dictated values (48.9%, SD 18.2%, P < .0001). MRI measured osteotomy angles averaged 67.2% of dictated values (SD 50.3%, P < .0001). The steepest osteotomy angle that could be performed without violating the posterior cortex and/or endangering the posterior neurovascular structures was 46.3°. CONCLUSIONS: Surgeons often overestimate both the anteriorization distance and the osteotomy angle in anteromedialization tibial tubercle osteotomies. The steepest osteotomy angle is less than the 60° described in the literature. Modifications should be considered when more anteriorization is desired with tubercle transfers. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) Scores > 55 at 6 Months Postoperative Predict Ability to Achieve Patient Acceptable Symptomatic State at Minimum 1 Year Postoperative Following Autologous Chondrocyte Implantation for Grade IV Chondral Defects About the Patellofemoral Joint.

PURPOSE: The primary aim is to evaluate the relationship between MOCART scores and patient satisfaction, as evaluated by achievement of (1) the Patient Acceptable Symptomatic State (PASS) and (2) the minimal clinically important difference (MCID) for Knee Injury and Osteoarthritis Score Quality of Life (KOOS QoL), for patients undergoing autologous chondrocyte implantation (ACI) for focal Grade IV patellofemoral chondral defects. The secondary aim is to determine the threshold MOCART score which predicts the ability to meet the PASS and the MCID for KOOS QoL. METHODS: Patients undergoing ACI for grade IV patellofemoral chondral defects by a single surgeon from 2017 to 2020 were identified by search of the EMR. To determine PASS status, patients were asked, "Do you consider your current level of symptoms to be acceptable?" KOOS QoL scores were also collected. Patients with 6-month postoperative knee MRI, PASS scores, and minimum 2-year follow-up data were included. Paired t tests and Wilcoxon Rank-Sum tests were used to evaluate the relationship between MOCART scores and (1) PASS achievement and (2) achievement of the MCID for KOOS QoL (12.8). RESULTS: Thirty-four patients were included, with a median age of 35.1 years [IQR: 24.6, 37.1], and BMI of 24.0 kg/m2 [IQR: 21.5, 28.1]. The median time to postoperative MRI was 6.7 months [IQR: 5.8, 7.9], and average follow-up time was 3.7 ± 1.2 years. Twenty-five patients (74%) achieved PASS, and 18 patients (out of 27 who had postop KOOS QoL Scores, 67%) achieved the MCID for KOOS QoL. Patients who achieved PASS had higher average MOCART scores (61.8 ± 16.0) than those who did not achieve PASS (45.0 ± 12.8, p=0.011), whereas patients who achieved the MCID for KOOS QoL did not have higher MOCART scores than those who did not achieve the MCID (61.9 ± 18.3 versus 53.3 ± 17.1, P = 0.25). There was no relationship between age, sex, lesion size, and lesion location and ability to achieve PASS or MCID for KOOS QoL (p>0.05). A threshold MOCART value of 55 was associated with the highest AUC on ROC analysis for likelihood of achieving PASS (0.778) and MCID for KOOS QoL (0.667). CONCLUSION: Higher MOCART scores are associated with an increased likelihood of achieving PASS following patellofemoral ACI. Moreover, MOCART scores > 55 predict the ability to achieve PASS and the MCID for KOOS QoL following patellofemoral ACI. LEVEL OF EVIDENCE: IV.

High Rates of Abnormal Patellofemoral Morphology in Adolescents With Anterior Knee Pain: A Retrospective Review.

Background: Anterior knee pain is a common reason for referral to a pediatric orthopedic surgeon. Although previous studies have found that adults with anatomic risk factors for patellofemoral instability (patella dislocation) are predisposed to anterior knee pain, no studies have elucidated the relationship between anatomic risk factors for patellofemoral instability and anterior knee pain in children. Purpose: We sought to characterize common radiographic findings in adolescent patients with a chief complaint of anterior knee pain and to determine the prevalence of abnormal patellofemoral morphology. Methods: We conducted a retrospective review of patients 13 to 18 years old with anterior knee pain at a single tertiary care metropolitan institution from 2016 to 2021. X-rays and magnetic resonance imaging (MRI) were evaluated in those diagnosed with "chondromalacia patellae," "chondromalacia," "patellofemoral disorders," or "anterior knee pain." Patella alta, tibial tubercle-trochlear groove (TT-TG) distance, tubercle height, Wiberg patella type, patellar tilt, and trochlear dysplasia characterization were recorded. Results: Of the 293 adolescents with anterior knee pain included, 62 had bilateral anterior knee pain. Of the 172 MRIs, 72 (42%) met criteria for patella alta, Caton-Deschamps Index (CDI) >1.3, 35% had a TT-TG distance >15 mm, and 32% had lateral patellar tilt >15°. Magnetic resonance imaging findings included infrapatellar fat pad signal hyperintensity (41%) and patellofemoral dysplasia (23%). Of all 293 adolescents, 74% had images showing abnormal patellofemoral morphology, of which 30% had a history of 1 or more patellar dislocation. Overall, 40% of the adolescents had surgery, most commonly medial patellofemoral ligament (MPFL) reconstruction (18%). Conclusions: In this retrospective review, nearly 3/4 of adolescents with anterior knee pain had images showing abnormal patellofemoral morphology, including patella alta, increased TT-TG distance, trochlear dysplasia, or abnormal lateral patellar tilt; only 18% had MPFL surgery. These findings suggest that primary care providers might consider obtaining X-rays and/or MRIs to evaluate for pathology that warrants orthopedic evaluation.

Combined Medial Quadriceps Tendon-Femoral Ligament and Medial Patellofemoral Ligament Reconstruction for Revision Patellofemoral Soft-Tissue Stabilization.

Patients with recurrent patellofemoral instability in whom prior medial patellofemoral ligament (MPFL) reconstruction fails present unique challenges for revision soft-tissue stabilization owing to scar tissue formation, limited patellar bone stock for anchor placement, and increased risk of patellar fracture. We describe a technique for revision patellofemoral soft-tissue stabilization that combines MPFL and medial quadriceps tendon-femoral ligament reconstruction techniques through combined fixation to the patella with 1 suture anchor and soft-tissue fixation to the quadriceps tendon. The proposed technique maximizes restoration of resistance to lateral translation by attempting to re-create the native MPFL attachment and minimizes patellar fracture risk in the setting of poor bone stock through the use of a single 1.8-mm all-suture suture anchor rather than bone tunnels or multiple anchor placement for bony fixation.